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AMC 12 2004 B

Question 1

At each basketball practice last week, Jenny made twice as many free throws as she made at the previous practice. At her fifth practice she made 48 free throws. How many free throws did she make at the first practice?

Solution

  
  2020-07-09 06:38:50

Question 2

In the expression , the values of , , , and are 0, 1, 2, and 3, although not necessarily in that order. What is the maximum possible value of the result?

Solution

  
  2020-07-09 06:38:50

Question 3

If and are positive integers for which , what is the value of ?

Solution

  
  2020-07-09 06:38:50

Question 4

An integer , with , is to be chosen. If all choices are equally likely, what is the probability that at least one digit of is a 7?

Solution

  
  2020-07-09 06:38:50

Question 5

On a trip from the United States to Canada, Isabella took U.S. dollars. At the border she exchanged them all, receiving 10 Canadian dollars for every 7 U.S. dollars. After spending 60 Canadian dollars, she had Canadian dollars left. What is the sum of the digits of ?

Solution

  
  2020-07-09 06:38:50

Question 6

Minneapolis-St. Paul International Airport is 8 miles southwest of downtown St. Paul and 10 miles southeast of downtown Minneapolis. Which of the following is closest to the number of miles between downtown St. Paul and downtown Minneapolis?

Solution

  
  2020-07-09 06:38:50

Question 7

A square has sides of length 10, and a circle centered at one of its vertices has radius 10. What is the area of the union of the regions enclosed by the square and the circle?

Solution

  
  2020-07-09 06:38:50

Question 8

A grocer makes a display of cans in which the top row has one can and each lower row has two more cans than the row above it. If the display contains 100 cans, how many rows does it contain?

Solution

  
  2020-07-09 06:38:50

Question 9

The point is rotated clockwise around the origin to point . Point is then reflected over the line to point . What are the coordinates of ?

Solution

  
  2020-07-09 06:38:50

Question 10

An annulus is the region between two concentric circles. The concentric circles in the ???gure have radii and , with . Let be a radius of the larger circle, let be tangent to the smaller circle at , and let be the radius of the larger circle that contains . Let , , and . What is the area of the annulus?

Solution

  
  2020-07-09 06:38:50

Question 11

All the students in an algebra class took a -point test. Five students scored , each student scored at least , and the mean score was . What is the smallest possible number of students in the class?

Solution

  
  2020-07-09 06:38:50

Question 12

In the sequence , , , , each term after the third is found by subtracting the previous term from the sum of the two terms that precede that term. For example, the fourth term is . What is the term in this sequence?

Solution

  
  2020-07-09 06:38:50

Question 13

If and with and real, what is the value of ?


Solution

  
  2020-07-09 06:38:50

Question 14

In , , , and . Points and lie on and , respectively, with . Points and are on so that and are perpendicular to . What is the area of pentagon ?

Solution

  
  2020-07-09 06:38:50

Question 15

The two digits in Jack's age are the same as the digits in Bill's age, but in reverse order. In five years Jack will be twice as old as Bill will be then. What is the difference in their current ages?

Solution

  
  2020-07-09 06:38:50

Question 16

A function is defined by , where and is the complex conjugate of . How many values of satisfy both and ?


Solution

  
  2020-07-09 06:38:50

Question 17

For some real numbers and , the equation has three distinct positive roots. If the sum of the base- logarithms of the roots is , what is the value of ?


Solution

  
  2020-07-09 06:38:50

Question 18

Points and are on the parabola , and the origin is the midpoint of . What is the length of ?

Solution

  
  2020-07-09 06:38:50

Question 19

A truncated cone has horizontal bases with radii and . A sphere is tangent to the top, bottom, and lateral surface of the truncated cone. What is the radius of the sphere?


Solution

  
  2020-07-09 06:38:50

Question 20

Each face of a cube is painted either red or blue, each with probability . The color of each face is determined independently. What is the probability that the painted cube can be placed on a horizontal surface so that the four vertical faces are all the same color?

Solution

First, figure out the total number of coloring combinations. It is 2 to the power of 6 as there are 6 faces in a cube.

Then divide the combinations that meet the requirement into 3 cases/scenarios:

1. all faces are painted the same color. There are 2 combinations.
2. any of the 5 faces are painted the same color. There are 2*6 combinations.
3. 4 faces are painted the same color in such a way so that the other 2 faces with different color are opposite each other. There are 2*3 combinations.

In no other cases/scenarios will the requirement be met. So the probability is (2*1+2*6+2*3)/2 to the power of 6.
  
jimmy  2016-10-01 22:23:23

Question 21

The graph of is an ellipse in the first quadrant of the -plane. Let and be the maximum and minimum values of over all points on the ellipse. What is the value of ?


Solution

  
  2020-07-09 06:38:50

Question 22

The square

is a multiplicative magic square. That is, the product of the numbers in each row, column, and diagonal is the same. If all the entries are positive integers, what is the sum of the possible values of ?

Solution

  
  2020-07-09 06:38:50

Question 23

The polynomial has integer coefficients and three distinct positive zeros. Exactly one of these is an integer, and it is the sum of the other two. How many values of are possible?

Solution

  
  2020-07-09 06:38:50

Question 24

In , , and is an altitude. Point is on the extension of such that . The values of , , and form a geometric progression, and the values of form an arithmetic progression. What is the area of ?


Solution

  
  2020-07-09 06:38:50

Question 25

Given that is a -digit number whose first digit is , how many elements of the set have a first digit of ?


Solution

  
  2020-07-09 06:38:50

Answer Keys


Question 1: A
Question 2: D
Question 3: A
Question 4: B
Question 5: A
Question 6: A
Question 7: B
Question 8: D
Question 9: E
Question 10: A
Question 11: D
Question 12: C
Question 13: A
Question 14: D
Question 15: B
Question 16: C
Question 17: A
Question 18: E
Question 19: A
Question 20: B
Question 21: C
Question 22: C
Question 23: C
Question 24: B
Question 25: B